THE BONES AXD JOIXTS. 



729 



between it and the bone. The outer layers of the periosteum may for a 

 long time resist the suppurative process. The accumulation of pus may 

 dissect up the membrane from the bone and leave the latter bare. The 

 pus thus formed may remain in this position for a long time, or be 



FIG. 481. OSSIFYING PERIOSTITIS TIBIA. 

 Large exostoses at the end of the bone. The process involves the joint and the bone is enlarged. 



absorbed, or become dry and cheesy, or it may burst through the perios- 

 teum and lead to abscesses in the soft parts. The bone, if separated from 

 its nutrient membrane, may remain unchanged, but more frequently 

 necrosis or inflammation of the bone itself is set up. Such a periostitis 

 may run an acute or a chronic course. 



Sometimes suppurative periostitis takes on a very malignant char< 

 acter. Pus is developed not only beneath, but in the periosteum, forming 

 abscesses filled with foul pus. The periosteum breaks down into a gan- 

 grenous, foul -smelling mass, and the same change may affect the neigh- 

 boring soft parts. The medulla may take part in the process and break 



FIG. 482. OSSIFYING PERIOSTITIS WITH LARGE EXOSTOSES FEMUR. 



A large part of the shaft is thickened and covered with ragged platelets of new-formed bone, while above 

 large rough exostoses project. This bone has been the seat of rarefying and formative osteitis. 



down into a purulent, gangrenous mass. Haemorrhages may complicate 

 the process. The lymph-nodes are enlarged and swollen ; abscesses may 

 form in different parts of the body, and the patient may die with the 



